Lee Juneyoung, Lee Dong Gun
School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Korea.
Exp Mol Med. 2008 Aug 31;40(4):370-6. doi: 10.3858/emm.2008.40.4.370.
To develop novel antibiotic peptides useful as therapeutic drugs, the enantiomeric analogue of pleurocidin (Ple), which is a well known 25-mer antimicrobial peptide, was designed for proteolytic resistance by D-amino acids substitution. The proteolytic resistance was confirmed by using HPLC after the digestion with various proteases. To investigate the antibiotic effect of L- and D-Ple, the antibacterial activity and hemolytic effect were tested against human erythrocytes. The D-Ple showed a decreased antibacterial activity and a dramatically decreased hemolytic activity compared with L-Ple. The hemolytic effect of analogue was further confirmed by using calcein leakage measurement with liposome. To elucidate these results, the secondary structure of the peptides was investigated by using circular dichroism spectroscopy. The results revealed that D-Ple, as well as L-Ple, had typical alpha-helical structures which were mirror images, with a different helicity. These results suggested that the discrepancy of the structure between the two peptides made their antibacterial activity distinct.
为开发用作治疗药物的新型抗生素肽，对已知的25肽抗菌肽pleurocidin（Ple）的对映体类似物进行设计，通过用D-氨基酸取代来提高其抗蛋白水解能力。在用各种蛋白酶消化后，通过高效液相色谱法（HPLC）确认了其抗蛋白水解能力。为研究L-Ple和D-Ple的抗菌效果，测试了它们对人红细胞的抗菌活性和溶血作用。与L-Ple相比，D-Ple的抗菌活性降低，溶血活性显著降低。通过使用脂质体钙黄绿素泄漏测量进一步证实了类似物的溶血作用。为阐明这些结果，使用圆二色光谱法研究了肽的二级结构。结果表明，D-Ple和L-Ple一样，具有典型的α-螺旋结构，它们是镜像结构，但螺旋度不同。这些结果表明，两种肽之间结构的差异导致了它们抗菌活性的不同。
